Add a debug message

.gitlab-ci.yml

@@ -7,6 +7,7 @@ cache:
   paths:
     - .tox
     - .cache/pip
+    - venv/
 
 stages:
   - test
@@ -17,12 +18,12 @@ before_script:
   - pip install virtualenv
   - virtualenv venv
   - source venv/bin/activate
-  - pip install .
 
 test:
   script:
     - pip install tox  # you can also use tox
     - pip install --editable ".[test]"
+    - python -c "import combo"
     - tox -e py